the temporal bone, temple (of the head)
顬 refers specifically to the temporal bone or the temple area of the head. It is a precise anatomical term rather than a word with broad conceptual extensions.
顬 combines 需 (phonetic component) with 頁 (head), forming a phono-semantic compound that specifically denotes the temporal bone or temple area.
The left side 需 looks like rain over a face, and the right side 頁 means head or page. Picture rain falling on the side of your head, right at the temple.
For ジュ, imagine a jewel (ジュエル) embedded in the temple of a statue: jewel -> ジュ, and the jewel sits right where the temporal bone is.